A background art discloses a serial printer that executes scanning with a print head and executes printing on a band basis. In an overlapping area where printing is executed through two scanning operations, this printer changes a ratio at which printing is executed through a first scanning operation and a ratio at which printing is executed through a second scanning operation according to a density in the overlapping area. As a result, the occurrence of a black streak or a white streak in the overlapping area can be suppressed.